ZURICH >> Soccer is falling under a cloud of suspicion as never before, sullied by a multibillion-dollar web of match-fixing that is corrupting increasingly larger parts of the world’s most popular sport.

Internet betting, emboldened criminal gangs and even the economic downturn have created conditions that make soccer — or football, as the sport is called around the world — a lucrative target.

Known as “the beautiful game” for its grace, athleticism and traditions of fair play, soccer is under threat of becoming a dirty game.

“Football is in a disastrous state,” said Chris Eaton, director of sport integrity at the International Centre for Sport Security. “Fixing of matches for criminal gambling fraud purposes is absolutely endemic worldwide … arrogantly happening daily.”

At least 50 nations in 2012 had match-fixing investigations — almost a quarter of the 209 members of FIFA, soccer’s governing body — involving hundreds of people.

Europol, the European Union’s police body, announced last week that it had found 680 “suspicious” games worldwide since 2008, including 380 in Europe.

Experts interviewed by The Associated Press believe that figure may be low. Sportradar, a company in London that monitors global sports betting, estimates that about 300 soccer games a year in Europe alone could be rigged.

“We do not detect it better,” Eaton said in an interview with the AP. “There’s just more to detect.”

Globalization has propelled the fortunes of popular soccer teams like Manchester United and showered millions in TV revenue on clubs that get into tournaments like Europe’s Champions League.

Criminals have realized that it can be vastly easier to shift gambling profits across borders than it is to move contraband.

“These are real criminals — Italian mafia, Chinese gangs, Russian mafia,” said Sylvia Schenk, a sports expert with corruption watchdog Transparency International.

Ralf Mutschke, FIFA’s security chief, admits that soccer officials had underestimated the scope of match-fixing. He told the AP that “realistically, there is no way” FIFA can tackle organized crime by itself, saying it needs more help from national law enforcement agencies.

The growing threat has prompted the European Union’s 27 nations to unite against match-fixing.

“The scale is such that no country can deal with the problem on its own,” said EU Sport Commissioner Androulla Vassiliou.

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Gambling on sports generates hundreds of billions of dollars a year, and up to 90 percent of that is bet on soccer, Interpol chief Ronald Noble told the AP in an interview. Eaton, the former FIFA expert, has cited an estimated $500 billion a year.

The total amount of money generated by sports betting would equal the gross domestic product of Switzerland, ranked 19th in the world.

Match-fixing — where the outcome of a game is determined in advance — is used by gambling rings to make money off bets they know they will win. Matches also are rigged to propel a team into a higher-ranking division where it can earn more revenue.

FIFA has estimated that organized crime takes in as much as $15 billion a year by fixing matches. In Italy alone, a recent rigging scandal is estimated to have produced $2.6 billion for the Camorra and the Mafia crime syndicates, Eaton said.

Soccer officials are well aware that repeated match-fixing will undermine the integrity of their sport, driving away sponsors and reducing the billion-dollar value of lucrative TV contracts.

FIFA earned $2.4 billion in broadcast sales linked to the 2010 World Cup in South Africa and already has agreed to $2.3 billion in deals tied to the 2018 World Cup in Russia. The U.K.’s Premier League earned $2.8 billion in broadcast rights for Britain alone in its last multiyear contract. Membership in Europe’s Champions League is worth nearly $60 million a year to each team, according to a lawsuit filed by the Turkish club Fenerbahce.

FIFA President Sepp Blatter has proclaimed “zero tolerance” for match-fixing, and FIFA has pledged $27 million to Interpol to fight it. Computer experts working for FIFA and UEFA — the European soccer body — monitor more than 31,000 European games and thousands of international matches every year, trying to sniff out the betting spikes that can reveal corruption.

So far, however, sports authorities are “proving to be particularly helpless in the face of the transnational resources” available to organized crime, according to a 2012 study on match-fixing. The report warned that the risk of soccer “falling into decay in the face of repeated scandals is genuine and must not be underestimated.”

Some top soccer officials shy away from the dire warnings of academics and law enforcement officials. UEFA chief Gianni Infantino said in a statement that, on average, 203 games — 0.7 percent of the matches that UEFA monitors a year — show some signs of irregularities, “which does not mean they are fixed.”

“It is a small problem, but it’s like a cancer,” Infantino said. “We don’t say 0.7 is nothing. We say 0.7 is 0.7 too much. We can say generally that UEFA competitions are very healthy in this respect.”

Match-fixing has been around for decades, of course, and is not limited to soccer. It has also infected sports like cricket, tennis, horse racing and even volleyball. The U.S. has its own sordid history of gambling scandals, from baseball’s Black Sox in the 1919 World Series to a handful of point-shaving schemes in college basketball over the years, to an NBA referee taking money from a professional gambler for inside tips on basketball games, including some that he officiated in 2007.

Still, nothing approaches the scale of the match-fixing allegations now hitting soccer, because of the sheer number of games played and the enormous Asian betting interest in European games, according to David Forrest, an economist at the U.K.’s University of Salford Business School, one of the co-authors of the 2012 report.

In January alone, FIFA banned 41 players in South Korea from soccer for life due to match-fixing. That follows 51 worldwide bans last year — 22 of them for life — on players, officials and referees from Croatia, Finland, Guatemala, Italy, Nicaragua, Portugal, South Korea and Turkey.

FIFA bans include some elite figures in the sport. Antonio Conte, coach of the Italian club Juventus — a team whose winning tradition rivals that of baseball’s New York Yankees — returned in December after a four-month ban for failing to report match-fixing.

Forrest’s report said that after the Sept. 11, 2001, attacks on the U.S., the war on terror relegated the fight against organized crime to a distinct second place, and that allowed gangs “to invest in new areas of the economy with relative impunity for nearly 10 years.”

Eaton attributes the surge in match-fixing to an exponential rise in online gambling — “at least 500 percent, and likely far more” — in the last decade.

Criminals have targeted every level of the game: the World Cup, regional tournaments such as the Champions League, high-powered divisions like England’s Premier League and Italy’s Serie A, “friendly” exhibition contests between national teams, all the way down to semipro games in the soccer wilderness.

Criminals are always trying to find the sweet spot between how poorly the players are paid and how much bettors want to wager on a game, Forrest said. That’s why fixers don’t try too hard to target the Super Bowl, he says, because “the bribes would be so high to convince the athletes to join.”

World Cup and European qualifiers that face uneven matchups are key targets because one team may “have no chance of getting into the tournament,” Forrest said in an interview.

The same scenario applies to early rounds of major tournaments or late-season national leagues, where one team is desperately trying to either win a trophy or avoid being sent down to a lower league. Those situations propel teams upward into a whole new level of revenue or send them tumbling off a financial cliff.

Match-fixing has also branched out from traditional hotbeds of corruption — Asia and the Balkans — to places like Canada, Finland and Norway, which rank among the least corrupt nations in the world. Until recently, no one — including sports regulators — thought to look for corruption in lower-level leagues. Still, given the vast amount of soccer betting, there’s plenty of money to be made.

“It’s liquidity of the markets,” Forrest said. “You can make serious money only if you can put on (bet) serious money. In most sports, the bet you can make is too small.”

Goalkeeper Richard Kingson of Ghana says he was offered — but declined — $300,000 to lose a game to the Czech Republic at the 2006 World Cup in Germany.

But prices have gone up. Italy’s Calciopoli investigation found it cost up to $516,000 to fix a match in the top league of Serie A; $155,000 for a fix in the second division and $64,500 for a third-division fixed match.

In Croatia, court documents show that first-league games in 2010 could be fixed for as little as $25,600.

There is also a shift in the traditional match-fixing scenario in which players are paid to lose or referees are paid to make sure one team wins. With the rise of online spot betting — wagers made during the game — criminal gangs can predetermine not only the outcome of the match but also make money on bets like how many goals are scored, when they are scored, or who will take a penalty kick.

These live bets can “be particularly advantageous for criminals,” according to Forrest’s report, because they increase the number of wagers placed on the same fixed game.

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As former Balkan warlords and Chinese businessmen have discovered, owning a club means players don’t need to be paid extra to fix matches; they can just be ordered to lose. Corrupt team officials have also dangled career advancement instead of money before vulnerable young players.

“There is an increasing worry about gangs taking over football clubs as a way to further match-fixing … and then they could also use the club to launder money,” Forrest said. “It’s quite cheap to buy a football club because so many of them are failing.”

An American diplomatic cable released by WikiLeaks quoted the U.S. Embassy in Sofia as reporting that “Bulgarian soccer clubs are widely believed to be directly or indirectly controlled by organized crime figures who use their teams as a way to legitimize themselves, launder money and make a fast buck.”

In 2011, Turkey’s venerable Fenerbahce soccer club won 16 of its last 17 national league games to stay in the coveted Champions League — a benefit it estimated as worth $58.5 million a year. In July 2012, Fenerbahce President Aziz Yildirim was convicted of fixing four of those games and bribing to influence the outcome of three others. He did it by promising rival players a roster spot or arranging for referees who would favor his team.

Yildirim was one of 93 people who went on trial in Turkey last year for match-fixing — and only 14 of them were players.

Serbian player Boban Dmitrovic says he saw many instances in his home country where two clubs simply agreed on the outcome in advance.

“Right before the match, a note was handed to the players. They had to cooperate because their careers would be jeopardized,” Dmitrovic told FIFPro, the soccer players’ union.

This “chairman-to-chairman method” of match-fixing is still common in Russia, Albania and the Balkan nations, according to Forrest’s sports corruption report.

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The vast majority of the world’s wagering originates in Asia, according to Forrest, but its own bettors shun that continent’s games for those in Europe because Asian soccer has been so corrupt for years.

In 2011, China’s main TV network refused to broadcast the country’s soccer games because match-fixing was so widespread. Last year, two former heads of China’s soccer federation were sentenced to 10½ years in prison.

In Finland, eight African players with ties to a Singapore crime gang were banned in 2012 for match-fixing. Their handler, Wilson Raj Perumal, was convicted of fixing games in Finland and is being investigated for allegedly fixing other matches in Europe and Africa. On Dec. 15, the South Africa Football Association said Perumal allegedly used tainted referees to manipulate games for betting purposes in 2010.

Experts say a typical scenario can go like this: Bookies set the odds for a game, not knowing it has been fixed. Right before the game starts, gangs unleash a torrent of bets, sometimes employing hundreds of poor workers on laptops. The wave hides the mastermind of the bet. If there is live wagering — on what the score will be at halftime or other topics — several bets can be made on the same fixed game.

Ninety or so minutes later, the bettors hand over their winnings to the boss.

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In the past, the perception was that greedy players were behind match-fixing. Yet a study of eastern Europe released last year by the FIFPro union portrayed a region where players often are not paid for months but instead are intimidated, blackmailed or beaten up.

Many said they had been approached by match-fixers — an average of 11.9 percent across the region, with spikes in Greece (30 percent) and Kazakhstan (34 percent). In Russia — host of the 2018 World Cup — about 10 percent of players had been approached to throw a game.

In four nations — the Czech Republic, Greece, Russia and Kazakhstan — at least 43 percent of players said they knew about tainted games in their leagues.

Almost 40 percent of the eastern European players who reported being asked to fix a game also said they had been victims of violence.

Zimbabwe’s national team players were threatened at gunpoint in the dressing room and ordered to lose matches by their own soccer officials in 2009, the country’s new federation chief, Jonathan Mashingaidze, said in an interview in December.

Sometimes the threat comes from a teammate. In Italy, a goalkeeper under heavy pressure from organized crime to fix a game in 2010 resorted to drugging several of his teammates so they would play badly. They did — and one even crashed his car after the match, prompting a police investigation that uncovered the fix.

Former player Mario Cizmek of Croatia says he agreed to fix one match in 2011 after he and his teammates had not been paid by his club for more than a year. That led to repeated demands by the fixer, a well-known former coach who used to drink at the same bar as Cizmek’s team. It was a classic case of a trusted acquaintance approaching a player to throw a match — a method that Forrest’s report says is used often.

“As a sportsman, I know I destroyed everything, but at the time I was only thinking about my family and setting things right,” Cizmek said in an interview.

Now broke, unemployed and divorced, Cizmek has been sentenced to 10 months in jail by a court in Zagreb.

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Because scoring in soccer is so low, its referees have an outsized influence on the game. In a Jan. 22 memo, FIFA urged its members to demand that referees tell soccer authorities immediately about “any suspicious situations, contact or information.”

“Our global experience is that referees and assistant referees are the primary target of match-fixers,” the memo said.

FIFA has been trying to improve its referee ranks with more training and taking proactive measures such as paying referees with checks instead of cash.

Dmitrovic said when fixed games in Serbia were not going according to plan, corrupt referees would step in with questionable calls to “achieve the desired result.”

“The referees always knew what was going on,” he said.

Tainted referees also are believed to be at the heart of one or more games involving South Africa in 2010, with a FIFA report in December finding “compelling evidence” of match-fixing.

In 2011, two friendly matches in the Turkish beach resort of Antalya — one between Bolivia and Latvia, the other between Bulgaria and Estonia — appeared suspicious when all seven goals came from penalty kicks awarded by referees. The German magazine Stern later reported that $6.9 million was wagered on the Bulgarian game alone.

FIFA banned the six eastern European officials involved in those games for life.

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Officials who govern the sport can’t stop match-fixing by themselves and need the cooperation of law enforcement bodies and governments across borders, said Schenk of Transparency International.

Noble, the Interpol chief, agreed.

“It’s definitely beyond and above the world of sport, above and beyond FIFA,” he said. “It’s fair to say we haven’t caught up to the scale of the problem.”

During the 2010 World Cup, police in China, Hong Kong, Macau, Malaysia, Singapore and Thailand arrested more than 5,000 people in Interpol-organized raids on nearly 800 illegal gambling dens. Interpol organized other raids in 2011 and 2012, but does not make arrests or conduct national investigations itself.

Schenk and the players’ union say soccer authorities must also make sure their own ranks are free of corruption. One World Cup ticket scandal was linked to the family of a senior FIFA vice president while the former head of Zimbabwe’s soccer federation is accused in a corruption scam.

“There is a strong link between good governance in the bodies that run sports and the sport organizations’ credibility in the fight against match-fixing,” Schenk wrote in a commentary. “Unless sport organizations are accountable and transparent, they will not have the authority to tackle the problem.”

Both Schenk and FIFA chief Blatter say whistleblowers must also be protected better.

In 2011, Italian defender Simone Farina turned down a fixer’s offer of $261,500 to throw a game and reported it to police, setting off an investigation that led to scores of arrests. Despite being honored by FIFA, he found himself shunned by many in Italy who considered him a snitch.

“I said no because my immediate thoughts were of my wife, son and daughter,” Farina said. “How could I look them in the eye if I said yes? What kind of husband and father would I be?”

Cizmek — the Croatian player who said he took $26,100 but handed back all but about $650 to police — says his scars from match-fixing will last a lifetime.

“This turned my life upside down,” he said. “I should have just taken my football shoes and hung them on the wall and said ‘Thank you, guys’ and gone on to do something else.”

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John Leicester in Paris, Graham Dunbar in Geneva, Gerard Imray in Johannesburg, Mike Corder in Amsterdam and Menelaos Hajicostis in Nicosia, Cyprus, contributed to this report.